Functional occlusion is a basic assumption for effective mastication related to its primary function of food intake and body nutrition. Mastication is necessary not only for food ingestion but also for promoting and maintaining the memory function. How is this possible?

Earlier studies emphasized importance of increased cerebral blood flow and activation of the brain cortex during activities of masticatory muscles. Increased oxygen supply thus positively supports the brain centers that are essential for cognitive processing, for memory and learning.

Sophisticated research of the brain structures and related functions based, for example, on functional magnetic resonance imaging shows surprising relationships between periodontal and pulp receptors including mechanoreceptors, proprioception receptors, nociceptive receptors and the hippocampus and prefrontal cortex. These brain structures play an important role in cognitive functions. Recent studies of both animals and humans prove that the hippocampus is negatively influenced by masticatory hypofunction. This is manifested by decreased density of pyramidal neurons and dendritic spines in the hippocampus. According to some studies the occlusion-mastication disharmony after the loss of several or more teeth may lead to cognitive impairment, especially in older people. Soft dieting can also cause occlusal hypofunction and degeneration of periodontal mechanoreceptors, followed by reduced sensory feedback from the oral cavity, affecting the hippocampus. Asymmetric masticatory muscle performance can lead to trigeminal nerve disbalance followed by cognitive impairment. Rehabilitation of occlusal harmony can improve the cognitive function. There is evidence of the reversibility of the hippocampal deficit. Some studies also report on the negative correlation between mastication and corticosteroids via the hypothalamic-pituitary-adrenal axis. It seems that mastication can inhibit stress responses.

There is evidence that occlusal hypofunction decreases the cognitive function and brain activities which may increase the risk for development of dementia in the elderly.

Maintaining good oral health together with functional occlusion is an important prevention of dementia.